Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Mary Elizabeth Callsen

Q: What is the NPI number for Mary Callsen?

The National Provider Identifier (NPI) for Mary Callsen is 1639137573, a Type 1 (individual) record in the CMS NPPES registry.

Internal Medicine Physician in Bethesda, MD · enumerated 2006.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1639137573

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Registry record

Entity type Individual (Type 1)

Name Dr. Mary Elizabeth Callsen

Sex Female

Practice address 7315 Wisconsin Ave, Bethesda, MD, 20814

Phone (240) 235-9100

Enumeration date May 2, 2006

Last updated in NPPES Jan 27, 2023

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License D0059499 (MD) Primary

Other identifiers

Identifier	Type	State	Issuer
1588055	Other	MD	CIGNA PROVIDER NUMBER
5770131	Other	MD	AETNA PPO PROVIDER NUMBER
61813201	Other	MD	BSMD PROVIDER NUMBER
8127031	Other	MD	MDIPA PROVIDER NUMBER
9070 0013	Other	MD	BSDC PROVIDER NUMBER
8127031	Other	MD	OPTIMUM CHOICE PROVIDER #
100797	Other	MD	JHHC PROVIDER NUMBER
521186611	Other	MD	UNITED HEALTHCARE PROV #
8127031	Other	MD	ALLIANCE PROVIDER NUMBER
5770131	Other	MD	AETNA HMO PROVIDER NUMBER
8127031	Other	MD	MAMSI PROVIDER NUMBER

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

Where does Mary Callsen practice?

The practice location on file with NPPES is in Bethesda, MD. Providers can have multiple locations; NPPES lists the primary practice address.

What is the NPI number for Mary Callsen?

The National Provider Identifier (NPI) for Mary Callsen is 1639137573, a Type 1 (individual) record in the CMS NPPES registry.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2023-01-27.